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DOI: 10.1055/s-2007-968462
Dynamic Kinetic Resolution of Aldehydes via Hydrogenation with Ruthenium
Contributor(s):Hisashi Yamamoto, Joshua N. PayetteNankai University, Tianjin, P. R. of China
Rh-Catalyzed Asymmetric Hydrogenation of Racemic Aldehydes via Dynamic Kinetic Resolution: Efficient Synthesis of Optically Active Primary Alcohols
J. Am. Chem. Soc. 2007, 129: 1868-1869
Publication History
Publication Date:
24 April 2007 (online)
Key words
ruthenium - hydrogenation - dynamic kinetic resolution
Significance
While chiral secondary alcohols are easily obtained from hydrogenation of the corresponding prochiral ketone, few methods for the synthesis of chiral primary alcohols exist by asymmetric hydrogenation. In this study, these substrates are obtained by the asymmetric hydrogenation of racemic α-branched aldehydes via dynamic kinetic resolution (DKR). An example of the utility of this system is demonstrated in the short synthesis of a biologically active compound.
Comment
The authors indicate that a bulky alkyl group at the α-position of the racemic aldehyde is essential for obtaining high asymmetric induction. Also, the position and electronic properties of substituents on the aryl ring seem to have little effect on enantioselectivites. Deuteration studies indicate that hydrogenation via DKR occurs at the carbonyl group rather than at the enol form of the aldehyde.